Taro Takahara

Background/Objectives: Mammography screening is limited by low sensitivity in dense breasts and by low participation, partly because of compression-related pain. We report the initial real-world outcomes of a non-population-based (opportunistic), non-contrast, compression-free breast cancer screening program based on DWIBS (DWIBS-BCS), distinguishing initial (prevalence) from subsequent screening. Methods: We retrospectively analyzed DWIBS-BCS examinations performed at a single center from January 2021 to December 2023, excluding examinations in women reporting a palpable lump. Two radiologists assigned four categories; category D was referred for diagnostic follow-up, and categories A–C were not systematically verified. Recall rate (RR), diagnostic follow-up completion rate (DFR), cancer detection rate (CDR), and positive predictive value (PPV) were calculated per examination with exact 95% confidence intervals (CIs) for initial, subsequent, and overall screening. Results: Of 554 DWIBS-BCS examinations, 506 were eligible: 360 initial (360 women) and 146 subsequent (107 women). All six screen-detected cancers occurred at initial screening. At initial screening, RR was 6.1% (22/360; 95% CI, 3.9–9.1%), DFR 81.8% (18/22; 95% CI, 59.7–94.8%), CDR 1.7% (6/360; 16.7 per 1000 examinations; 95% CI, 0.6–3.6%), and PPV 33.3% (6/18; 95% CI, 13.3–59.0%). No cancer was detected among 146 subsequent examinations. Five of the six screen-detected cancers were clinical stage 0 or I. In 36.8% (186/506) of examinations, the woman had never had mammography. Conclusions: In this self-selected cohort with incomplete outcome ascertainment, DWIBS-BCS detected six mostly early-stage cancers at initial screening. These preliminary, descriptive data are not comparable with organized-screening benchmarks and do not establish screening accuracy or clinical benefit; prospective studies with systematic outcome ascertainment are needed.

The purpose of this study was to evaluate the impact of progressive site-directed therapy (PSDT) for oligometastatic castration-resistant prostate cancer (OM-CRPC) on the efficacy of subsequent androgen receptor axis-targeted (ARAT) drugs, and to demonstrate the possibility of prolonging overall survival (OS). We performed a retrospective analysis of 15 OM-CRPC patients who underwent PSDT and subsequently received first-line ARAT drugs (PSDT group) and 13 OM-CRPC patients who were treated with first-line ARAT drugs without PSDT (non-PSDT group). PSDT was performed with the intention of treating all progressing sites detected by whole-body diffusion-weighted MRI with radiotherapy. Thirteen patients (86.7%) treated with PSDT had a decrease in PSA levels, which was at least 50% in 10 (66.7%) patients. The median PSA progression-free survival (PFS) for PSDT was 7.4 months. The median PSA-PFS for ARAT was 27.2 months in patients in the PSDT group and 11.7 months in the non-PSDT group, with a significant difference between the two groups (hazard ratio [HR], 0.28; p = 0.010). The median OS was not reached in the PSDT group and was significantly longer than 44.5 months in the non-PSDT group (HR, 0.11; p = 0.014). In OM-CRPC, PSDT may improve the efficacy of subsequent ARAT and OS.

To evaluate diffusion-weighted MR neurography (DW-MRN) for visualizing the brachial plexus and for the assessment of brachial plexopathy. 40 oncological patients with symptoms of brachial plexopathy underwent 1.5 T MRI using conventional MR sequences and unidirectional DW-MRN. The images were independently reviewed by two radiologists. Anatomic visualization of the brachial plexus was scored using a 5 point scale on conventional MR sequences and then combined with DW-MRN. A brachial plexus abnormality was also scored using a 5 point scale and inter-observer agreement determined by kappa statistics. Diagnostic accuracy for brachial plexopathy assessed by conventional MRI alone versus conventional MRI combined with DW-MRN was compared by ROC analysis using reference standards. DW-MRN significantly improved visualization of the brachial plexus compared with conventional MRI alone (P < 0.001). When assessing brachial plexopathy, inter-observer agreement was moderate for conventional MRI (kappa = 0.48) but good for conventional MRI with DW-MRN (kappa = 0.62). DW-MRN combined with conventional MRI significantly improved diagnostic accuracy in one observer (P < 0.05) but was similar in the other observer. DW-MRN improved visualization of the brachial plexus. Combining DW-MRN with conventional MRI can improve inter-observer agreement and detection of brachial plexopathy in symptomatic oncological patients.

Thanks to recent advances in magnetic resonance imaging technology, it has become possible to perform intravoxel incoherent motion (IVIM) diffusion‐weighted imaging (DWI) in any part of the body. Extracranial applications of DWI are currently under active investigation, especially for oncological imaging. However, the use of non‐quantitative low b‐value (10–100 s/mm²) DWI in the body is still a relatively unexplored field, and its potential is not fully recognized. Non‐quantitative low b‐value DWI may especially be useful for the evaluation of structures that have an inherently low signal at high b‐value DWI, including (but not limited to) the liver, heart, and small bowel. This article will review and discuss the basic principles and potential applications of nonquantitative low b‐value DWI in the body. J. Magn. Reson. Imaging 2012;35:1266–1273.

Purpose: To introduce and assess the TRacking Only Navigator echo (TRON) technique for diffusion-weighted magnetic resonance imaging (DWI) of the liver. Subjects and Methods: A total of 10 volunteers underwent TRON, respiratory triggered (RT), and free breathing (FB) DWI of the liver. Scan times of TRON and RT DWI were measured, and image sharpness in TRON, RT, and FB DWI was assessed and compared using nonparametric tests. Furthermore, 14 patients with liver metastasis who had undergone TRON and RT DWI of the liver were retrospectively assessed. Relative contrast ratios (RCRs) and apparent diffusion coefficients (ADCs) of the largest hepatic metastasis in TRON and RT DWI were measured. RCRs were compared using a parametric test and agreement in ADCs was assessed using the Bland-Altman method. Results: In the volunteers, mean scan times of TRON and RT relative to FB DWI were 110% to 112% and 261% to 290%, respectively. On axial images, there were no significant differences in images sharpness among TRON, RT, and FB DWI, but on coronal images image sharpness in TRON was nearly always significantly better (P < 0.05) than in RT and FB DWI. In the patients, mean RCRs between TRON and RT DWI were not significantly different (P = 0.9091). Mean difference in ADC ± limits of agreement (in 10⁻³ mm²/s) between TRON and RT DWI was −0.16 ± 0.79. Conclusion: TRON offers sharp diffusion-weighted images of the liver using an efficient scan time, making it an excellent alternative to RT and FB DWI. The moderate to poor agreement in ADCs of liver metastases between TRON and RT DWI requires further investigation.

Background This technical note introduces diffusion-weighted (DW) MR neurography (MRN) of the sacral plexus with unidirectional motion probing gradients (MPGs). Methods This is compared with DW MRN with three-directional and six-directional MPGs. Results and conclusion This paper indicates that DW MRN of the sacral plexus should be performed with unidirectional MPGs.